package com.ssm.maven.core.util;

import java.awt.Graphics;
import java.awt.Image;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.math.BigDecimal;
import java.math.MathContext;
import java.util.ArrayList;

import javax.imageio.ImageIO;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/*** 
 * 对图片进行操作 
 */
public class ImageHelper
{

    private static Logger logger = LoggerFactory.getLogger(ImageHelper.class);

    private static ImageHelper imageHelper = null;

    public static ImageHelper getImageHelper() {
        if (imageHelper == null)
        {
            imageHelper = new ImageHelper();
        }
        return imageHelper;
    }

    /*** 
     * 按指定的比例缩放图片 
     * 
     * @param sourceImagePath 
     *      源地址 
     * @param destinationPath 
     *      改变大小后图片的地址 
     * @param scale 
     *      缩放比例，如1.2 
     */
    public static void scaleImage(String sourceImagePath, String destinationPath, double scale, String format) {

        File file = new File(sourceImagePath);
        BufferedImage bufferedImage;
        try
        {
            bufferedImage = ImageIO.read(file);
            int width = bufferedImage.getWidth();
            int height = bufferedImage.getHeight();

            width = parseDoubleToInt(width * scale);
            height = parseDoubleToInt(height * scale);

            Image image = bufferedImage.getScaledInstance(width, height, Image.SCALE_SMOOTH);
            BufferedImage outputImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
            Graphics graphics = outputImage.getGraphics();
            graphics.drawImage(image, 0, 0, null);
            graphics.dispose();

            ImageIO.write(outputImage, format, new File(destinationPath));
        }
        catch (IOException e)
        {
            logger.info("scaleImage方法压缩图片时出错了");
            e.printStackTrace();
        }
    }

    /*** 
     * 按指定的宽度缩放图片，高度自适应 
     * 
     * @param sourceImagePath 
     *      源地址 
     * @param destinationPath 
     *      改变大小后图片的地址 
     * @param width_scale 
     *      缩放后的宽度 
     */
    public static void scaleImage(String sourceImagePath, String destinationPath, int width_scale, String format) {

        File file = new File(sourceImagePath);
        BufferedImage bufferedImage;
        try
        {
            bufferedImage = ImageIO.read(file);
            int width = bufferedImage.getWidth();
            int height = bufferedImage.getHeight();

            double scale = getDot2Decimal(width_scale, width);
            width = parseDoubleToInt(width * scale);
            height = parseDoubleToInt(height * scale);

            Image image = bufferedImage.getScaledInstance(width, height, Image.SCALE_SMOOTH);
            BufferedImage outputImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
            Graphics graphics = outputImage.getGraphics();
            graphics.drawImage(image, 0, 0, null);
            graphics.dispose();

            ImageIO.write(outputImage, format, new File(destinationPath));
        }
        catch (IOException e)
        {
            logger.info("scaleImage方法压缩图片时出错了");
            e.printStackTrace();
        }

    }

    /*** 
     * 将图片缩放到指定的高度或者宽度 
     * @param sourceImagePath 图片源地址 
     * @param destinationPath 压缩完图片的地址 
     * @param width 缩放后的宽度 
     * @param height 缩放后的高度 
     * @param auto 是否自动保持图片的原高宽比例 
     * @param format 图图片格式 例如 jpg 
     */
    public static void scaleImageWithParams(String sourceImagePath, String destinationPath, int width, int height,
            boolean auto, String format)
    {
        try
        {
            File file = new File(sourceImagePath);
            BufferedImage bufferedImage = null;
            bufferedImage = ImageIO.read(file);
            if (auto)
            {
                ArrayList<Integer> paramsArrayList = getAutoWidthAndHeight(bufferedImage, width, height);
                width = paramsArrayList.get(0);
                height = paramsArrayList.get(1);
                logger.info("自动调整比例，width=" + width + " height=" + height);
            }

            Image image = bufferedImage.getScaledInstance(width, height, Image.SCALE_DEFAULT);
            BufferedImage outputImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
            Graphics graphics = outputImage.getGraphics();
            graphics.drawImage(image, 0, 0, null);
            graphics.dispose();
            ImageIO.write(outputImage, format, new File(destinationPath));
        }
        catch (Exception e)
        {
            logger.info("scaleImageWithParams方法压缩图片时出错了");
            e.printStackTrace();
        }

    }

    /** 
     * 将double类型的数据转换为int，四舍五入原则 
     * 
     * @param sourceDouble 
     * @return 
     */
    private static int parseDoubleToInt(double sourceDouble) {
        int result = 0;
        result = (int) sourceDouble;
        return result;
    }

    /*** 
     * 
     * @param bufferedImage 要缩放的图片对象 
     * @param width_scale 要缩放到的宽度 
     * @param height_scale 要缩放到的高度 
     * @return 一个集合，第一个元素为宽度，第二个元素为高度 
     */
    private static ArrayList<Integer> getAutoWidthAndHeight(BufferedImage bufferedImage, int width_scale,
            int height_scale)
    {
        ArrayList<Integer> arrayList = new ArrayList<Integer>();
        int width = bufferedImage.getWidth();
        int height = bufferedImage.getHeight();
        double scale_w = getDot2Decimal(width_scale, width);

        logger.info("getAutoWidthAndHeight width=" + width + "scale_w=" + scale_w);
        double scale_h = getDot2Decimal(height_scale, height);
        if (scale_w < scale_h)
        {
            arrayList.add(parseDoubleToInt(scale_w * width));
            arrayList.add(parseDoubleToInt(scale_w * height));
        }
        else
        {
            arrayList.add(parseDoubleToInt(scale_h * width));
            arrayList.add(parseDoubleToInt(scale_h * height));
        }
        return arrayList;

    }

    /*** 
     * 返回两个数a/b的小数点后三位的表示 
     * @param a 
     * @param b 
     * @return 
     */
    public static double getDot2Decimal(int a, int b) {

        BigDecimal bigDecimal_1 = new BigDecimal(a);
        BigDecimal bigDecimal_2 = new BigDecimal(b);
        BigDecimal bigDecimal_result = bigDecimal_1.divide(bigDecimal_2, new MathContext(4));
        Double double1 = new Double(bigDecimal_result.toString());
        logger.info("相除后的double为：" + double1);
        return double1;
    }

}
